1. Field of the Invention
The invention relates to a method of cooling a grate for a furnace and to a grate for a furnace. Grates of the generic type are used in furnaces, e.g. of refuse-incineration plants. The cooling is effected for the purpose of increasing their useful life by reducing the scaling of the grate material under the action of the combustion heat.
2. Discussion of Background
Thus it is known, for instance, from DE-A-44 09 992 to cool a grate bar by water which is directed through a passage which is run in the longitudinal direction from the rear end of the grate bar up to the tip and back through the grate bar. The effect of this type of cooling is restricted by the convective heat transfer and by the heat-absorption capacity of the water, as results from its thermal capacity and the temperature range available. The temperature of the cooling water must be kept below the boiling point, a factor which requires a relatively high velocity of flow to be maintained in the entire volume. The manufacture of the grate bars is thus inevitably relatively complicated and the cooling arrangement which maintains the cooling-water circulation is costly.
EP-B-0 621 449 discloses a similar design of a grate, in which, however, the grate bars of one row are in each case replaced by a continuous grate plate. Here, sufficient cooling with relatively low heating of the cooling water is ensured by large cross sections of flow, but this again requires a large cooling-water flow rate, which in turn can only be maintained by an expensive cooling arrangement.